The delivery times are looooooooong. But that may not be a problem. I feel safer buying in TomTop than in AliExpress, I don't know why. Before my order arrive I felt like I had made a mistake, but everything arrived nicely packed and, well, I have no complaints. The Customer Service is Ok, they reply moderately fast (days, not hours), but this is legit. No problems on my end. Be careful as always when buying from China, but I would say there is no real risk.
If you have a problem, however... I guess you would leave a negative review.